6. Based on the configured loggers, the results are being rendered to the console, a textfile or other output formats. The output can be checked manually or processed automatically.

Karma is highly configurable, the most important configurations are:

The list of files to load in the browser (app.js)

The testing framework which is used (e.g. jasmine) has to be configured and appropiate plugins have to be loaded - note that this also determines the html page (test.html) because it is framework specific

The list of browsers (can be a headless one like phantom.js, too) to launch and run tests in

The list of log appenders (console, textfile...) to be used

Note that 2., 3. and 4. support a plugin mechanism, i.e. Karma will load appropriate plugins. Such plugins are available for the most common scenarios, for more exotic scenarios you could write them on your own.